Tanaka T, Minamino H, Unezaki S, Tsukatani H, Tokumura A
Faculty of Pharmaceutical Sciences, University of Tokushima, Japan.
Biochim Biophys Acta. 1993 Feb 24;1166(2-3):264-74. doi: 10.1016/0005-2760(93)90107-k.
We have identified novel phospholipids together with platelet-activating factor and its 1-acyl analogues in purified fractions from a bovine brain lipid extract. These novel compounds were phospholipids with an sn-2-short-chain monocarboxylyl, dicarboxylyl or omega-hydroxymonocarboxylyl group. The profiles of these three types of phospholipids suggest that they were formed by lipid peroxidation. To examine this possibility, we peroxidized synthetic phosphatidylcholines (PC) with an sn-2-polyunsaturated fatty acyl group and PC from bovine brain, with Fe2+/ascorbate/EDTA, and analyzed the secondary degradation products retaining a glycerol backbone by fast atom bombardment-mass spectrometry and GC-MS. Results showed the formation of four kinds of PC with a short-chain monocarboxylate, dicarboxylate, dicarboxylate semialdehyde or omega-hydroxymonocarboxylate moiety. The chain lengths of these PC were related to the position of the double bond vicinal to the esterified carbonyl group in the sn-2-long-chain acyl moiety of the parent PC. The molecular heterogeneity of secondary products formed by the oxidative degradation of bovine brain PC resembled those of the unique phospholipids that we previously detected in the fractions with platelet-activating factor-like activity purified from a bovine brain lipid extract, although the former lacked the species with an acetyl group. These results suggest that all the novel phospholipids with a short-chain acyl group in the brain lipid extract except that with an acetyl group were produced by lipid peroxidation.
我们在牛脑脂质提取物的纯化组分中鉴定出了新型磷脂，以及血小板活化因子及其1-酰基类似物。这些新型化合物是具有sn-2-短链单羧基、二羧基或ω-羟基单羧基基团的磷脂。这三种类型磷脂的图谱表明它们是由脂质过氧化形成的。为了检验这种可能性，我们用Fe2+/抗坏血酸/乙二胺四乙酸对具有sn-2-多不饱和脂肪酰基的合成磷脂酰胆碱（PC）以及牛脑PC进行过氧化处理，并通过快原子轰击质谱和气相色谱-质谱分析保留甘油主链的二级降解产物。结果显示形成了四种带有短链单羧酸盐、二羧酸盐、二羧酸盐半醛或ω-羟基单羧酸盐部分的PC。这些PC的链长与母体PC的sn-2-长链酰基部分中与酯化羰基相邻的双键位置有关。牛脑PC氧化降解形成的二级产物的分子异质性与我们之前在从牛脑脂质提取物中纯化的具有血小板活化因子样活性的组分中检测到的独特磷脂相似，尽管前者缺少带有乙酰基的种类。这些结果表明，脑脂质提取物中除带有乙酰基的以外，所有具有短链酰基的新型磷脂都是由脂质过氧化产生的。
